Basically, the projector with the solid-state light source has the following three types of light source systems: lasers, light emitting diodes (LEDs), and a combination of laser and light emitting diodes. Laser light source system usually uses blue laser with fluorescence wheel or phosphor wheel, and the fluorescent wheel contains phosphor layer for exciting red beam or phosphor layer for exciting green beam. LED light source system usually comprises a light emitting diode module for emitting red light, a light emitting diode module for emitting green light and a light emitting diode module for emitting blue light. The light source system with a combination of laser and light emitting diodes usually uses blue laser with fluorescence wheel, wherein the fluorescent wheel contains phosphor for exciting red beam or phosphor for exciting green beam, and the beam with the rest colors are emitted by light emitting diode or laser with specified wavelengths.
Generally, the existing technology uses dichroic mirror to combine the red, green and blue beams provided by the respective light source modules. However, due to the physical limitation of the dichroic mirror, only one of the red, green or blue light source modules is selected to use. Therefore, when the brightness of image display needs to enhance, either the power of each light source module or the quantity of laser or light emitting diodes in each light source module is required to increase. However, the aforementioned approaches may lead to the following problems: (1) the photoelectric conversion efficiency decreases if simply increasing the power of the light source module, further, the increase in power may disproportionate to the increase in the brightness and the brightness may be saturated; and therefore, the brightness may not be enhanced by indefinitely increasing the power; (2) the component size of the light source system may increase and the entire volume of the light source system may become large if simply increasing the quantity of laser or light emitting diodes; (3) the etendue may increase if simply increasing the quantity of laser or light emitting diodes, and the brightness may not be able to enhance any longer by increasing the quantity of laser or light emitting diodes if the etendue has a mismatch with the designing configuration of the projector or the etendue reaches to the maximum.
The information disclosed in this “BACKGROUND OF THE INVENTION” section is only for enhancement understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Furthermore, the information disclosed in this “BACKGROUND OF THE INVENTION” section does not mean that one or more problems to be solved by one or more embodiments of the invention were acknowledged by a person of ordinary skill in the art.